The present invention relates to a cart and, in particular, to a cart having a frame that includes at least one shelf and a tray assembly coupled to the frame above the shelf. More particularly, the present invention relates to a tray assembly that is removable from the cart frame so that the tray assembly can be used as a serving tray or lap tray away from the cart.
Shelf structures and carts have a variety of uses around a home, office, or other work place. These devices typically include vertically extending legs to which one or more fixed shelves are attached. The legs and shelves together form a frame. Each shelf includes a surface on which items may be placed for display and storage.
Carts often include wheeled casters that are attached to the lower end of each of the legs. These wheeled casters enhance the mobility of a cart so that the items on the cart shelves can be simultaneously and more easily transported from one location to another by a user pushing the cart.
Transferring items from a cart shelf to a separate tray to expedite delivery of the items can be a cumbersome and time-consuming activity. If many items must be transferred, someone must find a place to set the tray next to the cart and the time and place to move the items from the cart shelf to the separate serving tray. Individual transfer of several items from a cart to a serving tray can involve considerable expenditure of time and, thus, quickly becomes inefficient. Another problem arises if additional tray storage space is not available to hold a tray when such tray is not in use.
Conventional tray assemblies typically include a tray having a table surface and a bottom surface. One type of tray assembly includes support legs on the bottom surface to elevate its table surface and another type of tray assembly has a generally flat bottom surface without any support legs.
Free-standing tray assemblies typically include two or more support legs coupled to the bottom surface of the tray. Short free-standing tray assemblies are used for such things as bed trays where a meal on the table surface of the tray can be enjoyed by an individual who is bedridden due to an illness. Tall free-standing trays are used as "TV trays" where an individual can enjoy a meal in a relaxed setting away from a dining room. In some designs, tray support legs are movable from a retracted position, where the legs are folded to lie flat against the bottom surface of the tray, to an extended position, where the legs are unfolded to project at an angle away from the bottom surface of the tray. The retracted position allows the tray assembly to be stored more easily, while the extended position allows the tray assembly to be self-supporting.
One problem with tray assemblies, free-standing or otherwise, is that they must be stored when not in use. Adequate storage space or a special rack must be provided to hold such tray assemblies when not in use. Both storage space and tray racks add to the expense associated with tray assemblies.
A cart or other shelf structure that incorporated a removable tray assembly as one of its shelves would allow the advantages of both to be exploited while, at the same time, reducing the above-described disadvantages associated with using separate carts and trays. Transportable items could be initially stored on the table surface of the tray assembly mounted on the cart. These items could be moved away from the cart, when desired, by removing the tray assembly from the cart frame and moving the tray to the desired location. The remaining shelves of the shelf structure or cart would still be employable for storage and display of other items. The frame of the shelf structure or cart would serve as a mounting fixture on which to store the tray assembly when not in use.
According to the present invention, a shelf structure includes a frame and a tray assembly. The shelf structure further includes means for mounting the tray assembly to the frame so that the tray assembly is connected to the frame and means for uncoupling the tray assembly from the frame so that a user can lift the tray assembly off of the frame to disconnect the mounting means from the frame.
In preferred embodiments, the frame includes four legs and at least one shelf coupled to the legs so that the frame is a free-standing structure. The shelf has a shelf surface on which items may be placed for storage and display. One of the ends of each of the legs may rest on a floor or other surface for support. Preferably, the shelf structure is a push cart having wheeled casters connected to the support ends of each of the legs of the frame. These wheeled casters allow the cart to be moved easily so that items stored and displayed on the one or more shelf surfaces can be transported from one place to another.
The tray assembly includes a tray having an upwardly facing table surface on which items are placed and a downwardly facing bottom surface. The bottom surface of the tray includes a plurality of leg mounts that are each configured to include a cavity that receives one of the top ends of each of the legs. The leg mounts allow the tray assembly to be connected to the top of the shelf structure above the shelf surface of the shelf immediately below to form the top tier of the shelf structure.
A pair of latch assemblies are attached to the bottom surface of the tray assembly that are configured to couple and uncouple the tray assembly to the frame of the shelf structure. Each latch assembly includes at least one latch and means for guiding each latch between a locked position engaging the frame to couple the tray assembly to the frame and an unlocked position disengaged from the frame to uncouple the tray assembly from the frame.
Each leg of the shelf structure is formed to include a latch-receiving slot. Each latch assembly is configured to include a handle. The handle allows the latch or latches of each latch assembly to be manually moved between a locked position engaging one of the latch-receiving slots and an unlocked position disengaging the latch-receiving slot. The latch handles also provide a convenient means for carrying the tray assembly when it is disconnected from the shelf structure.
The latch assemblies are biased so that the latches are urged to their locked positions. One or more springs are used to bias each of the latches to its locked position. Each of these springs is positioned to lie in a spring pocket formed between a latch assembly and the tray bottom surface. Each latch of the biased latch assemblies is moved against its spring to its unlocked position. The latches are moved simultaneously to an unlocked position by manually applying a force to each of the handles in a direction generally opposite the force applied by the springs.
In a preferred embodiment, a rounded cap is mounted on the top of each leg and each cap is formed to include a latch-receiving slot. Essentially, the rounded top portion of the cap acts as a cam and functions to cam each spring-biased latch toward its tray-releasing position during mounting of the tray on the legs. By providing such a latch cam mechanism on each leg, a user can install the tray simply by positioning the tray in a proper position above the legs and pushing down on the tray until the spring-loaded latches are cammed to a tray-releasing position and then snap back into the latch-receiving slots formed in the leg caps.
The tray assembly further includes a pair of tray stands coupled to the bottom surface of the tray. Each tray stand is movable between a retracted position adjacent the bottom surface and an extended position supporting the tray. The extended position makes the tray assembly suitable for use, for example, as a bed or "TV" tray. The tray stands are typically moved to the retracted position when the tray is connected to the cart so that they are out of the way of objects stored on the shelf surface of the immediately lower shelf. Tray stand clamp assemblies couple the tray stands to the bottom surface of the tray and secure them in the retracted position as well as the extended position.
Each tray stand includes a pair of legs that are connected together by a cross-brace which is configured to include a raised portion. At least one snap lock is cantilevered to the bottom surface of the tray adjacent the position assumed by each cross-brace when the tray stands are in the retracted position. The snap locks engage the raised portions of the cross-braces to help secure the tray stands in the retracted position.
The tray assembly can be easily reconnected and coupled to the shelf structure when it is no longer desired to use the tray separately. First, the tray stands are moved to the retracted position. A user locates the tray in a proper position so that the top ends of the legs are inserted into the downwardly facing leg mount cavities of the tray assembly to connect the tray assembly to the frame. The user pushes down on the tray so that the latches are moved against their springs to their tray-releasing positions. The latches are urged automatically by their springs to their tray-locking positions into the slots formed in the leg caps. This couples the tray assembly to the frame of the shelf structure.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.